Vehicle with convertible wheels

Abstract

This vehicle includes a frame having inboard rail bearing wheels and outboard carriages carrying ground bearing wheels. The carriages are mounted to opposite sides of the frame for vertical movement in a guide system provided at each side of the frame and each carriage provides a mounting for fore and aft ground wheels. A counterbalance system is used to facilitate raising the carriages independently of each other from a ground engaging mode to a retracted mode and a latching system holds the carriages in place in each mode.

I claim as my invention: 
     
       1. A convertible vehicle with wheels comprising: (a) a frame including a longitudinal axis and having guide means on each side thereof,   (b) spaced front and rear rail bearing wheels mounted to the frame in rotatable relation on each side of said axis,   (c) a pair of carriages each received in sliding relation by an associated guide means on one side of said frame for vertical movement of each carriage relative to said frame from an upper retracted position to a lower position, each carriage including spaced front and rear ground engageable wheels rotatably mounted to the carriage for vertical movement with said carriages,   (d) counterbalance means including constant force spring means operatively connected between the frame and each carriage to facilitate movement of said carriages between the upper and lower positions, and   (e) means for selectively holding the carriages in the upper and lower positions.   
     
     
       2. A vehicle as defined in claim 1, in which: (f) the means for holding the carriages in position include cooperating latch means on the frame and the carriages at each end of the carriages.   
     
     
       3. A vehicle as defined in claim 2, in which: (g) the latch means includes a movable pivoted latch element at each end of each carriage and a plurality of vertically disposed fixed latch elements on the frame selectively receiving said movable elements in latched relation.   
     
     
       4. A vehicle as defined in claim 1, in which: (f) each carriage includes front and rear ends, and   (g) the counterbalance means includes first connection means at each end of said carriage, second connection means carried by said frame adjacent said carriage ends and a constant force spring would thereon and operatively extending between said first and second connection means.   
     
     
       5. A vehicle as defined in claim 1, in which: (f) the guide means includes cooperating vertically disposed tongue and groove elements, one of said elements being carried by the frame and the other of said elements being carried by the carriage to limit relative fore and aft movement of said carriage.   
     
     
       6. A vehicle as defined in claim 1, in which: (f) the guide means includes cooperating vertically disposed members attached to said frame in overlapping relation to each end of said carriage to limit relative outward movement of said carriage.   
     
     
       7. A vehicle as defined in claim 1, in which: (f) the frame includes spaced pairs of notched members disposed on each side thereof inboard of the carriages, and   (g) each rail bearing wheel includes a shaft received by said notched members and a U-bolt connecting said axle to said notched members.   
     
     
       8. A vehicle as defined in claim 1, in which: (f) each carriage includes front and rear end members interconnected by inner and outer longitudinal side members,   (g) said ground engageable wheels are rotatably mounted between said side members and between said front and rear end members, and   (h) the frame includes front and rear relatively outstanding portions disposed adjacent said front and rear carriage ends and receiving said carriage therebetween.   
     
     
       9. A vehicle as defined in claim 8, in which: (i) said frame outstanding portions include stop means overlappingly related to each end of said carriage to limit relative outward movement of said carriage.   
     
     
       10. A vehicle as defined in claim 7, in which: (i) each of said ground engageable wheels includes a shaft mounted between said inner and outer carriage members, and   (j) said carriage outer member includes a pocket portion receiving said shaft whereby said shaft is recessed inwardly of said carriage.   
     
     
       11. A vehicle as defined in claim 7, in which: (i) the means for holding the carriages in position include a movable latch element carried by each end of each carriage and a plurality of vertically disposed latch openings on each outstanding member selectively receiving said movable latch elements in latched relation.   
     
     
       12. A vehicle as defined in claim 11, in which: (j) the latch openings include upper, lower and intermediate openings receiving said movable latch element to define upper, lower and intermediate wheel positions.   
     
     
       13. A vehicle as defined in claim 11, in which: (j) the latch element at each end of each carriage is rotatable and includes a pivoted locking member operatively engageable with a frame outstanding member to lock the latch element in the selected position.   
     
     
       14. A vehicle with convertible wheels comprising: (a) a frame including a longitudinal axis and having guide means on each side thereof,   (b) spaced front and rear rail bearing wheels mounted to the frame in rotatable relation on each side of said axis,   (c) a pair of carriages each received in sliding relation by an associated guide means on one side of said frame for vertical movement of each carriage relative to said frame from an upper retracted position to a lower position, each carriage including spaced front and rear ground engageable wheels rotatably mounted to the carriage for vertical movement with said carriages,   (d) counterbalance means operatively connected between the frame and each carriage to facilitate movement of said carriages between the upper and lower positions,   (e) means for selectively holding the carriages in the upper and lower positions,   (f) each carriage including front and rear ends interconnected by inner and outer longitudinal side members,   (g) said ground engageable wheels being rotatably mounted between said side members,   (h) the frame including front and rear relatively outstanding portions disposed adjacent said front and rear carriage ends and receiving said carriage therebetween,   (i) said outstanding portions providing housings, and   (j) said counterbalance means including a spool mounted within each housing, each spool having at least one constant force spring having one end wound on said spool, and the other end being connected to an adjacent end of said carriage means.   
     
     
       15. A vehicle with convertible wheels comprising: (a) a frame including a longitudinal axis and having guide means on each side thereof,   (b) spaced front and rear rail bearing wheels mounted to the frame in rotatable relation on each side of said axis,   (c) a pair of carriages each received in sliding relation by an associated guide means on one side of said frame for vertical movement of each carriage relative to said frame from an upper retracted position to a lower position, each carriage including spaced front and rear ground engageable wheels rotatably mounted to the carriage for vertical movement with said carriages,   (d) counterbalance means operatively connected between the frame and each carriage to facilitate movement of said carriages between the upper and lower positions,   (e) means for selectively holding the carriages in the upper and lower positions,   (f) each carriage including front and rear ends interconnected by inner and outer longitudinal side members,   (g) said ground engageable wheels being rotatably mounted between said side members,   (h) the frame including front and rear relatively outstanding portions disposed adjacent said front and rear carriage ends and receiving said carriage therebetween,   (i) said outstanding portions providing housings,   (j) said counterbalance means including a spool mounted within each housing, each spool having at least one constant force spring having one end wound on said spool, and the other end being connected to adjacent ends of said carriage means,   (k) each end of each carriage including a depending portion having a longitudinally extending portion,   (l) each outstanding portion of said frame including a cut-out portion receiving said carriage extending portion, and   (m) said other end of said spring being connected to said extending portion.   
     
     
       16. A convertible vehicle with wheels comprising: (a) a frame including a longitudinal axis and having guide means on each side thereof,   (b) spaced front and rear rail bearing wheels mounted to the frame in rotatable relation on each side of said axis,   (c) a pair of carriages each received in sliding relation by an associated guide means on one side of said frame for vertical movement of each carriage relative to said frame from an upper retracted position to a lower position, each carriage including spaced front and rear ground engageable wheels rotatably mounted to the carriage for vertical movement with said carriage,   (d) counterbalance means at each end of each carriage operatively connected between the frame and each carriage to facilitate movement of said carriages between the upper and lower positions, and   (e) means for selectively holding the carriages in the upper and lower positions.   
     
     
       17. A convertible vehicle as defined in claim 16, in which: (f) each carriage extends longitudinally beyond the front and rear wheels, and   (g) the frame includes stop means to limit transverse movement of the ends of the carriages relative to the frame.